Table 1. Summary of Efficacy Studies on Dyes.

Author	Number of cases	Agent	Tattooed area	Efficacy (%)	Invisible (%)
Beretvas and Ponsky [11]	15	Methylene blue	Colon	100	0
Miyoshi et al [8]	41	Indocyanine green	Colon	92.7	7.3
Hammond et al [9]	15	Indocyanine green	Colon	100	0
Aboosy et al [7]	19	India Ink	Colon	68.4	31.5
Cho et al [1]	96	India Ink	Colon	97.9	2.1
Shatz et al [12]	55	India Ink	Colon	NA	NA
McArthur et al [13]	195	India Ink	Colon	100	0
Arteaga-Gonzalez et al [14]	21	India Ink	Colon	100	0
Shaffer et al [15]	19	India Ink	Esophagus	94.7	5.3
Sun et al [16]	53	India Ink	Stomach	96.2	3.8
Feingold et al [17]	50	Purified carbon	Colon	88	12
Askin et al [18]	113	Purified carbon	Colon	100	0
Park et al [19]	63	Purified carbon	Colon	96.8	1.6

NA: not available.