['Photodynamic therapy with aminolevulinic acid (ALA-PDT) is effective therapy for acne vulgaris; however, relatively strong side effects limit its wide usage. We have previously demonstrated that ALA-induced protoporphyrin IX distribution with lower concentrations and shorter contact time of ALA resulted in focused damage in sebaceous glands in vivo. We have formulated a protocol for ALA-PDT using 5% ALA with 2 hours contact time. The objective of this study was to establish the effectiveness and side effect profile of the new protocol in humans.', "Eleven Japanese patients (Fitzpatrick's skin type III - IV, mean age 23.7±7.2) with facial acne received topical application of 5% ALA for 2 hours with subsequent illumination by a broadband light (600 - 1100 nm, 15J/cm(2), 60 mW/cm(2)). Subjects were evaluated prior to the procedure, 1 month, and 3 months after the treatment by a blinded dermatologist using the global acne grading system (GAGS). Side effects were monitored through the treatment period.", 'The mean GAGS score decreased from 22.1±3.8 at baseline to 19.4 at 1 month, and to 16.3 at 3 months after PDT (P<0.05). Ten of eleven patients experienced local side effects, such as erythema, which were of minimal to mild severity. However, most side effects were of minimal to mild severity, and all of them resolved within several days without post inflammatory hyper pigmentation.'] Is photodynamic Therapy with 5 % δ-Aminolevulinic Acid Safe and Effective Treatment of Acne Vulgaris in Japanese Patients?