Two cases of garlic and darunavir interaction have been reported. In the first case, a 27-year-old HIV positive man on tenofovir/emtricitabine (200/245 mg [sic], once daily) and darunavir/ritonavir (800/100 mg, once daily) suffered an increase in HIV viral load. After investigation he was found to have subtherapeutic Ctroughs for darunavir and ritonavir. He reported consuming 15 cloves of garlic a week. A month after ceasing to take garlic, darunavir and ritonavir Ctroughs were in the expected range. In the second case a 41-year-old HIV positive woman on abacavir/lamivudine (600/300 mg, once daily) and darunavir and ritonavir (600/100 mg, twice daily) also experienced increased HIV viral load and subtherapeutic darunavir and ritonavir Ctroughs. She disclosed an undetermined but significant intake of garlic. Again, one month after ceasing garlic consumption, darunavir and ritonavir Ctroughs returned to expected levels. The authors hypothesise a herb-drug interaction occurred via induction of P-gp expression and activity by garlic. They state that it may be difficult to predict herb-drug interactions with garlic as the effect may depend on the preparation of garlic, estimated consumption, and time of exposure.