CP94, an iron chelator, enhances protoporphyrin IX photobleaching and reduces the viability of A431 squamous epithelial carcinoma cells at a 150 µM concentration with photodynamic therapy (PDT) using protoporphyrin IX precursors such as aminolevulinic acid (ALA), methyl aminolevulinate (MAL), or hexylaminolevulinate (HAL). Additionally, CP94 (2 mg/ml in drinking water) lowers hepatic non-heme and ferritin-bound iron levels while increasing hepatic protoporphyrin levels in mice. It also counteracts ferrocene-induced rises in rat brain iron levels at a dosage of 100 mg/kg.