The effect of the extract of U & Dee Sweet Bitter, a Nigerian herbal remedy on the kidney was investigated in matured Wistar albino rats. Twenty male albino rats were allocated into four dose groups of five rats each, namely 0.00, 539, 1077, 1616 mg/kg of the herbal product orally for 90 days. Animals had access to deionized water and were fed ad libitum with rat chow for 90 days. The feed and fluid consumption of the animals were measured on daily basis, and the body weight was measured weekly. After 90 days, the animals were anaesthetized with ether, bled, sacrificed, kidney excised, and weighed. The parameters measured included food and fluid intake, body weight, absolute and relative weight of the kidney. A nonsignificant increase (p > .05) in feed and fluid intake occurred in all treated animals and a significant decrease (p < .05) in absolute weight of the kidney in all the treated animals when compared with the control. The administration of 539, 1077, and 1616mg/kg of U & Dee Sweet Bitter caused a significant (p < .05) dose-dependent increase in creatinine, whereas a significant dose-dependent decrease for urea was noted compared with the control. Histological study showed that U & Dee Sweet Bitter at all doses caused renal pathologic changes that include tubular necrosis, inflammation of the interstitial and glomerulus, and disorganization of the entire architecture. The results are indicative of nephrotoxicity.