We carried out animal experiments to toxicologically verify polysulphide poisoning by analyzing tissue samples. A bathing agent containing calcium polysulphides was administered orally to rats, and then polysulphides and sulphide, the decomposed product of polysulphides, were analyzed by GC and GC/MS. The concentrations of polysulphides (mumol/ml or g) were found to be highest in blood (0.196), followed by the liver (0.051), the lungs (0.018) and kidneys (0.013), but were below the detection limit (0.005 mumol/g) in the other tissues tested. Sulphide was detected in all the tissue samples and was found to be highest in the blood (0.518 mumol/ml), this being 40 times higher than that required for fatal poisoning in the case of hydrogen sulphide. Polysulphide poisoning was considered to be confirmatively diagnosed by detecting and measuring polysuphides and supplementarily sulphide in body tissues, most pertinently in the blood. Two practical cases of suspected poisoning by polysulphides are briefly described.