Foscan е противопоказен за хора, които биха могли да проявят свръхчувствителност (алергични реакции) към темопорфин или някоя от другите съставки.
Foscan must not be used in patients with porphyria (an inability to break down porphyrins), other diseases made worse by light, allergy to porphyrins, or tumours that are spreading into a blood vessel or that are next to where the laser is to be shone.