Table 1.

Effect of green tea and decaffeinated green tea on UVB-induced complete carcinogenesis.

Treatment	Number of keratoacanthomas per mouse	Number of squamous cell carcinomas per mouse
Water	5.75 ± 1.04	1.17 ± 0.27
Green tea	2.21 ± 0.46*	0.52 ± 0.18*
Decaf. green tea	4.58 ± 0.64	1.35 ± 0.29
Caffeine	1.81 ± 0.44*	0.63 ± 0.14*
Decaf. green tea + caffeine	2.53 ± 0.43*	0.47 ± 0.11*

Female SKH-1 mice were treated with UVB (30 mJ/cm²) twice weekly for 40 weeks. Tea leaf extracts (1.25 gm tea leaf/100 ml hot water; 4 mg tea solids/ml) or caffeine (0.36 mg/ml) were administered as the drinking fluid during the entire period of UVB irradiation and for an additional 4 weeks. Each value is the mean ± SE from 24 to 30 mice. *P < 0.05. Taken from Huang et al. (1997).