A, Amoxapine treatment successfully delayed or suppressed CPT-11-induced diarrhea in tumor-bearing mice. Amoxapine 1mg/kg/day (Amox-1mg) or 5mg/kg/day (Amox-5mg), or inhibitor I 1mg/kg/day (Inhibitor-I) was orally administered twice per day along with daily i.p. CPT-11 treatment. N=15 mice per group. * p<0.05; **p<0.01, by Fisher Exact Test. B, Amoxapine treatment improved the survival of CPT-11-treated tumor-bearing mice. By the Log-rank test, CPT-11 vs. Amox-5mg, p=0.004. C, Amoxapine in combination with CPT-11 achieved addictive effect in suppressing tumor growth. Amoxapine was gavaged at 1mg/kg/day or 5mg/kg/day for 12 days with daily i.p. injection of CPT-11. Tumor volumes were estimated by the formula π/6 × a2 × b, where a is the short axis, and b the long axis. * p<0.05; **p<0.01, by Two-way ANOVA analysis, taking time and group as factors. Sigma Plot software was used to calculate the P value.