The results showed that UGT1A1*28 wild-type (TA6/6) had a higher incidence of grade 0–2 thrombocytopenia compared with mutant type (TA6/7 + TA7/7) [RR = 1.13, 95%CI (0.96, 1.33), P = 0.15], but there was no statistically significant difference in the results (P > 0.05); (2) Grade 3–4: A total of six studies were included in the recessive gene model (TA6/6 vs. TA6/7 + TA7/7), and the heterogeneity analysis showed that it was I2 = 0%, P = 0.55, and there was no statistical heterogeneity among the studies. This evidence concerns the gene UGT1A1 and Thrombocytopenia.