Red birthmark, medically partly called a nevus, is a kind of hemangioma, which is a flattened and rarely elevated plaque composed of numerous dilated capillaries and is a congenital capillary malformation. Some of them are also true hemangiomas. Some of these lesions increase in size as the body grows and do not subside throughout life, and can occur in any part of the body, with the face and neck being the most common. The incidence is as high as 3 per 1,000 in newborns. There are many treatment methods for red birthmarks, including isotope, freezing, pulsed dye laser light and other methods, most of which are not effective and easily damage the skin and produce scars. Photodynamic therapy is a new method of red birthmark treatment, based on the interaction of light, photodynamic drugs and oxygen as a new means of disease treatment. A new photodynamic drug, Hemoporfin for injection, has recently begun to make its presence felt in the field of treatment of erythema nodosum. It is a new monomeric porphyrin-based photodynamic drug that can be rapidly cleared from tissues due to its well-defined structure and rapid metabolism, and has low toxic effects on normal tissues – both acute and long-term toxicity are lower than that of the first-generation photodynamic drug hematoporphyrin derivatives. The tolerability and pharmacokinetics of injectable hemoporphyrin in healthy subjects were studied at the National Pharmaceutical Clinical Research Base. The results showed that Hemiporfin for injection was safe and tolerable in the dose range for the healthy Chinese subjects enrolled in the study, and no photosensitivity side effects occurred in all subjects.