1,2,3-Trichloropropane (1,2,3-TCP) is an industrial water contaminant with potential for human exposure by the oral route. The systemic toxicology of 1,2,3-TCP was evaluated after subacute or subchronic exposure in male and female Sprague-Dawley rats. Animals were treated with 0.01, 0.05, 0.20 and 0.80 mmol per kg per day for 10 days and 0.01, 0.05, 0.10 and 0.40 mmol per kg per day for 90 days. Chemical exposure was by oral gavage in corn oil. Lethality did not occur in either study. Toxicity was observed primarily in the high dose group of subacute and subchronically treated rats of both sexes. The primary histological finding in the study was an inflammation-associated cardiopathy produced by 1,2,3-TCP. Myocardial necrosis and degeneration occurred in a diffuse pattern with marked eosinophilia of affected cells. Male and female animals showed a cardiopathic response only at a dose of 0.8 mmol per kg 1,2,3-TCP after the 0-day exposure. In the subchronic study, the incidence of cardiopathy was more prevalent in males than in females. In addition to cardiac effects, the 90-day chemical exposure produced bile duct hyperplasia in 40% and 80% of males and females, respectively. The observation may be significant, since five other neoplastic and proliferative lesions were observed in rats receiving 1,2,3-TCP subchronically. Thus, the study demonstrates that heart and liver were target organs for 1,2,3-TCP toxicity and suggests that 1,2,3-TCP exposure may be involved in carcinogenesis.