To study the involvement of age and inflammation in motor colonic activity in man, contractile responses to CCK, carbachol, and KCl of isolated colonic smooth muscle cells (SMC) from normal and inflamed human colons were evaluated; the incidence of sex and smoking on contraction was also analyzed. Contractile responses to the three agonists were significantly lower in tissues with a low degree of inflammation than in tissues with high level of inflammation or normal tissues. This reduction in cell responsiveness appears to be nonspecific and nonreceptor mediated. A positive correlation of the contractile responses to the three stimulants with the age of patients was observed. In contrast, no association was found between sex, smoking, and cell contraction. In conclusion, contractions of SMC due to CCK, carbachol, and KCl were significantly modified during life; inflammation of the colon led to a loss of SMC responsiveness.