Compounds for use The invention relates to a combination comprising (i) a compound A comprising a mitochondrial targeting group linked to a group capable of releasing hydrogen sulfide or a pharmaceutically acceptable salt thereof or a prodrug thereof, an inhibitor of the thioredoxin antioxidant system or pharmaceutically acceptable salt thereof or a prodrug thereof, and/or a nitroxide or a pharmaceutically acceptable salt thereof or a prodrug thereof; and (ii) a photosensitizer or photosensitizer precursor; for use in photodynamic therapy.