"Natural" doesn't mean "no interactions". Several spices in capsule form can change how medicines work. This table is a starting point for a conversation with your pharmacist, not a replacement for one.
| If you take… | Take extra care with | Why |
|---|---|---|
| Blood thinners or aspirin | Garlic, turmeric, ginger, black seed, fenugreek | May add to bleeding risk |
| Diabetes medicines or insulin | Fenugreek, black seed, cinnamon, turmeric, moringa | May add to blood-sugar lowering |
| Blood-pressure medicines | Black seed, garlic, ashwagandha, cayenne | May add to the effect, or (cayenne) worsen ACE-inhibitor cough |
| Thyroid medicine | Ashwagandha, moringa | May affect thyroid hormone levels |
| Sedatives or sleep medicine | Ashwagandha | May add to drowsiness |
| Antiretrovirals, transplant or epilepsy medicines | Turmeric + black pepper, garlic, cayenne | Piperine and garlic can change medicine levels |
| Antidepressants | Saffron | May add to the effect |
Before surgery
Stop garlic, ginger, turmeric, black seed and ashwagandha supplements about two weeks before planned surgery or dental extraction, and tell your surgeon what you have been taking.
Sources
Last reviewed 19 October 2026 by Spicewell editorial team. How we write our guides