Natural does not mean free of interactions
St John's wort, ginkgo and green tea clash with very common medicines. The box does not say so.
A medicinal plant is a medicine: it has active principles, so it has effects and it has interactions. Being sold without a prescription does not make it harmless.
Three examples we see at the counter:
· **St John's wort** speeds up how the body clears other drugs. It can reduce the effectiveness of oral contraceptives, anticoagulants and some antidepressants — and reduced effectiveness is not something you notice until something happens.
· **Ginkgo** and other plants can add to the effect of an anticoagulant.
· **Green tea in high doses** (extracts, not a cup) also interferes with some treatments.
None of this means they should not be taken. It means that **whoever sells them needs to know what else you take**, and that is precisely a pharmacy's job.
If you take plants or supplements, bring the list of everything you take — prescribed and not — and we will go through it in five minutes. And when we give herbal advice, we give it having looked at that list first, not just at what you came in for.