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Cancer in dogs and cats · Aug 27, 2015

Three herbs with real evidence behind them for pet cancer

Artemisia annua, turmeric, and rooibos won’t replace your vet, but the research behind them is solid enough that brushing them off would be a mistake.

Golden dog and tabby cat beside sweet wormwood, turmeric root and rooibos — herbs with cancer evidence for pets

By Beryl Shuttleworth, BSc Hons Biochem

Last reviewed: 2026-06-12

A handful of herbs genuinely stand out here, not as cures, but as compounds with real biological activity worth knowing about. Artemisia annua (sweet wormwood) selectively kills cancer cells in vitro and in animal models, and a retrospective clinical study found dogs and cats getting an *A. annua* preparation alongside standard treatment survived significantly longer than controls. Curcumin, turmeric’s active compound, hits multiple canine cancer cell lines in the lab, but here’s the catch: oral bioavailability is terrible without specialist formulation, so what reaches the tumour matters enormously. Rooibos (*Aspalathus linearis*) has reduced tumour development in rodent models, which puts it more in the prevention camp than treatment.

In vitro results mean these herbs are proven cancer treatments for pets

I get why people leap to this conclusion. You read that artemisinin kills cancer cells, or that curcumin induces apoptosis in canine osteosarcoma lines, and it feels like the case is closed. I’ve looked at those same studies, they’re genuinely exciting. But there’s a real gap between a cell dying in a Petri dish and a tumour shrinking in a living dog, and the industry, plus plenty of enthusiastic online communities, routinely glosses right over it.

Let’s start with curcumin, since it’s the one most owners reach for first. The in vitro anti-cancer effects happen at micromolar concentrations. Give curcumin orally, even at a high dose, and peak plasma levels in dogs come in at around 4-5 ng/mL. That’s nanomolar territory. Improved formulations like phospholipid complexes can bump that up 5-15 fold, but you’re still nowhere near the tissue concentrations that produce those cell-culture results [7]. And here’s the telling bit: a pilot clinical trial that used intravenous liposome-encapsulated curcumin in dogs with metastatic cancer, the most bioavailability-optimised delivery route you can get, achieved stable disease in four of six dogs who completed treatment, but found no radiographic tumour shrinkage at all [6]. That’s not a dismissal of curcumin; it’s just what the actual clinical data says.

The translation problem isn’t curcumin’s alone. Researchers working across this whole field openly acknowledge that cytotoxic activity in cell culture is inconsistent and difficult to predict once you’re in a living animal, and that in vivo clinical trials are needed before anyone can make proper efficacy claims [11]. A systematic evidence review came to the same conclusion, the science isn’t yet strong enough to define clinical efficacy for most herbal and botanical cancer therapies in companion animals [10].

The Artemisia annua picture is more encouraging, and that’s precisely because there is actual in vivo data. A retrospective study of 20 dogs and cats treated with standard therapy plus an *A. annua* preparation found significantly higher survival beyond 18 months compared to controls [3]. A small case series reported survival of 26-40 months in sarcoma patients, against the typical 7-12 months for surgery alone [2]. That is genuinely promising. It’s also a small, uncontrolled body of evidence that warrants larger trials, not a licence to call it a proven cure.

None of this means these herbs are useless. What it means is that the honest position is “promising, mechanistically plausible, and in need of more clinical data”, not “proven treatment.” Any company or commentator telling you otherwise is outrunning the evidence, and I think you deserve better than that.

How these herbs act against cancer cells

Let’s start with sweet wormwood (Artemisia annua), because the evidence here is genuinely interesting. The plant contains artemisinin, a compound that in vitro studies show selectively kills cancer cells and triggers apoptosis, basically, it prompts cancer cells to self-destruct. That same effect has held up in animal models too, including implanted fibrosarcoma tumours in rats and naturally occurring tumours in veterinary patients.

What makes the mechanism particularly clever is the iron angle. Cancer cells tend to hoard iron, and artemisinin exploits that, it’s preferentially toxic to iron-loaded cells. A retrospective study of 20 dogs and cats backs this up nicely: those treated with a standardised A. annua preparation called Luparte alongside standard therapy had significantly higher survival beyond 18 months compared to controls on standard therapy alone. Immunohistochemical analysis from that study found a correlation between tumour transferrin receptor (TfR) expression, a marker of iron uptake, and how well the animals responded to artemisinin. A smaller case series of four pets with sarcoma treated with surgery plus Luparte recorded survival times of 26-40 months, against the typical 7-12 months for surgery alone.

The in vitro work on canine osteosarcoma cell lines (D-17, OSCA-8, OSCA-40) adds another layer: a hydroalcoholic extract of A. annua produces dose-dependent cytotoxic effects, and phytochemical analysis shows the extract contains not just artemisinin but also scopoletin and arteanuine B. The evidence points to these compounds working together synergistically, rather than artemisinin carrying the whole load by itself.

Now, curcumin, the principal active compound in turmeric (Curcuma longa). In cell culture, it’s impressive: anti-cancer activity across canine mastocytoma, mammary carcinoma, osteosarcoma, and bladder cancer cell lines, working through cell cycle arrest, apoptosis induction, and inhibition of metastatic markers. Turmeric and rosemary extracts even showed synergistic effects together in canine cell culture models.

Here’s the honest part, though, and I’d rather tell you than not: oral bioavailability of unformulated curcumin in dogs is a real problem. Peak plasma concentrations reach only about 4-5 ng/mL even at high doses, and the concentrations that produce those impressive anti-cancer effects in cell culture are at the micromolar level, far above what standard oral dosing achieves in a living animal. Phospholipid complex formulations can improve bioavailability 5-15 fold, but even those remain well short of what the in vitro studies use.

Finally, rooibos (Aspalathus linearis). In rat models, unfermented rooibos reduced oesophageal papilloma size by 87% and inhibited skin tumorigenesis by 60-75% when applied topically prior to tumour promotion. In vitro, rooibos extracts inhibited cancer cell proliferation and induced apoptosis at significantly lower concentrations in cancer cells than in normal cells, which is exactly what you want from a selective anti-cancer agent.

How to use these herbs in practice, what the evidence actually supports

Artemisia annua (Sweet Wormwood)

So, the clinical work on this herb, both the case series [2] and the 20-dog/cat retrospective study [3], used a proprietary preparation called Luparte, given alongside standard therapy (usually surgical tumour removal). It wasn’t used instead of conventional treatment; it was added on top of it. And survival times in the treated groups were substantially longer than in controls.

One thing worth flagging from the research: tumour transferrin receptor (TfR) expression correlates with artemisinin responsiveness [3]. In plain terms, not every tumour is going to respond equally. The studies focused on sarcomas, which tend to be iron-loaded, that’s the tumour type where the evidence sits. If a biopsy has been taken, it’s worth asking your oncologist about TfR status.

Now, the research pool doesn’t contain a validated weight-based oral dosing protocol for dogs or cats outside the Luparte preparation, and I’m not going to invent one. What I will tell you is that the in vitro cytotoxic work used a hydroalcoholic extract of the whole plant, not isolated artemisinin, and the phytochemical evidence points to synergistic activity among multiple compounds: artemisinin, scopoletin, and arteanuine B all appear to be contributing [4]. So a whole-plant preparation is more consistent with what’s actually been studied than a single isolated-artemisinin product.

On tolerability: across both the case series and the retrospective study, A. annua was well tolerated with no noticeable side effects [2][3]. These were small observational studies rather than dedicated safety trials, so take that for what it is, but the signal is reassuring.

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Turmeric / Curcumin (Curcuma longa)

Right, I need to be honest with you here, because there’s a real tension in this evidence. The in vitro data on curcumin is genuinely interesting, across canine mastocytoma, mammary carcinoma, osteosarcoma, and bladder cancer cell lines, you see cell cycle arrest, apoptosis induction, and inhibition of metastatic markers [5]. Good stuff, on paper. The problem is what happens when curcumin actually has to get into a living dog.

Oral bioavailability is severely limited. Unformulated curcumin achieves only 4-5 ng/mL peak plasma concentration in beagle dogs even at doses as high as 150 mg/kg. Even fancy bioavailability-enhanced formulations, phospholipid complexes, solid dispersions, only get you to nanomolar tissue concentrations. The anti-cancer effects in vitro happen at micromolar concentrations [7]. That’s not a small gap; it’s a meaningful one.

The pilot clinical trial of IV liposome-encapsulated curcumin in dogs with metastatic cancer did show stable disease in 4 of 6 dogs completing treatment, but no radiographic tumour shrinkage, and some dogs experienced anaemia and vomiting [6].

If you do choose to use turmeric: formulation really matters. Go for a bioavailability-enhanced form, phospholipid complex or similar, rather than plain turmeric powder [7]. And it’s worth knowing that turmeric and rosemary extracts showed synergistic effects in canine cell culture models [5], which is useful context if you’re building a broader supplement protocol.

Cautions you should take seriously: high chronic doses can cause gastrointestinal problems, anaemia, and changes in liver epithelial tissue in dogs [8]. Curcumin chelates iron, so long-term high-dose use carries a genuine risk of iron-related anaemia [8]. That’s particularly important to bear in mind if you’re also using Artemisia annua, which itself interacts with iron metabolism. The research pool doesn’t define a safe upper dose for dogs in a cancer context, so I won’t quote one, but please don’t assume that more is better here, because the evidence says otherwise.

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Rooibos (Aspalathus linearis)

The animal model evidence for rooibos is chemopreventive in nature, reducing tumour development, inhibiting skin tumour promotion, reducing esophageal papilloma size, rather than therapeutic in established cancer [9]. So I’d frame its use as a sensible dietary addition for general cancer prevention, not as an active treatment once cancer is already present. Brewed rooibos tea added to food or water is the most practical delivery route, and it’s consistent with how the research was framed. No toxicity or contraindication data for pets appears in the research pool.

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A word on evidence quality

More than half of pet owners whose dogs have cancer are already using nutraceutical or herbal supplements [12]. I completely understand why, conventional options are often brutal, and the urge to do something more is entirely reasonable. But I’d be doing you a disservice if I pretended the evidence base is stronger than it is. Most of the data comes from cell culture, rodent models, or small observational studies, and translation from in vitro effects to living animals is genuinely inconsistent [10][11]. Use these herbs as adjuncts to veterinary care, not substitutes for it.

One more thing: human-formulated supplements can be outright toxic to cats at human doses, lipoic acid is the documented example [12]. Always cheque species appropriateness before reaching for anything formulated for people.

What we’d recommend


Artemisia annua (Wormwood)

Artemisia annua’s artemisinin shows real anti-cancer activity in dogs and cats, watch this space.

See the product

Frequently asked questions

Does Artemisia annua actually work against cancer in dogs and cats?

Honestly, the evidence is more than just theoretical, it’s genuinely encouraging. In the lab, artemisinin selectively kills cancer cells by generating reactive oxygen species inside iron-rich tumour cells. But what really caught my attention was a retrospective study of 20 dogs and cats: those given an Artemisia annua preparation alongside standard therapy had significantly higher survival beyond 18 months compared to controls on standard therapy alone. Small studies, yes, but the signal keeps showing up consistently.

What survival times have been reported for pets with sarcoma given Artemisia annua?

In a case series of four pets, one cat and three dogs, with sarcoma, surgery plus an Artemisia annua herbal preparation (Luparte) produced survival times of 26 to 40 months. Surgery alone typically gives you 7 to 12 months, so that’s a striking difference. The preparation was well tolerated with no noticeable side effects, though the researchers themselves say we need larger controlled trials before drawing firm conclusions. Fair enough, but I’d want those numbers on my side.

Does it matter which part of Artemisia annua is used, pure artemisinin or the whole plant extract?

It matters more than you might think. In vitro work on canine osteosarcoma cell lines found that the whole hydroalcoholic extract of Artemisia annua contains not just artemisinin but also scopoletin and arteanuine B, and there’s evidence these compounds work synergistically. So if you’re reaching for isolated artemisinin, you’re probably leaving efficacy on the table. A whole-herb extract is the more sensible choice, and the research backs that up.

Can curcumin from turmeric reach tumour cells in dogs when given orally?

This is the awkward truth about oral curcumin, and I’m not going to sidestep it. Even at high doses, plain unformulated curcumin only hits around 4-5 ng/mL peak plasma concentration in dogs. The anti-cancer effects seen in cell culture happen at micromolar concentrations, miles above that. The good news is that phospholipid complex or solid dispersion formulations can push bioavailability up 5-15 fold, which is why formulation really does matter if you’re using curcumin with any therapeutic intent.

Are there any side effects of giving curcumin or turmeric to dogs long-term?

At very high chronic doses, curcumin can cause gastrointestinal upset, anaemia, partly through iron chelation, and changes to liver epithelium in dogs. That said, toxicological studies show doses up to 4-8 g/kg produce no apparent poisoning, so the risk at sensible supplemental levels is low. Where I’d urge more caution is in dogs that are already anaemic, particularly if you’re also using Artemisia annua, which works alongside iron loading. In that scenario, long-term high-dose curcumin warrants monitoring.

Is rooibos useful for a pet that already has cancer, or only as prevention?

Right now, the evidence best supports rooibos (Aspalathus linearis) as a chemopreventive agent rather than a treatment for established cancer. Animal studies showed it reduced esophageal papilloma size by 87% and inhibited skin tumorigenesis by 60-75% when used before tumour promotion. In vitro, it does induce apoptosis preferentially in cancer cells, which is interesting, but there are no clinical trials in dogs or cats with active cancer. Prevention is where the evidence sits, and that’s where I’d apply it.

Should I tell my vet if I’m giving my pet herbal supplements alongside cancer treatment?

Yes, absolutely, no question. Survey data show over 50% of pet owners whose dogs have cancer are already using herbal or nutraceutical supplements, and most vets are open to the conversation. The real risk isn’t disapproval, it’s interactions and dosing errors, especially because some human-formulated supplements are outright toxic to cats at human doses. Your vet also needs the full picture to make sense of any changes in bloodwork or treatment response. Don’t leave them guessing.

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