Colorectal cancer (CRC) is the fourth most common cause of malignant tumor death. The development of novel, more effective drugs is desperately needed to treat CRC. Zingiber officinale is believed to possess anticancer properties due to its flavonoids and phenols. Using Soxhlet (SOXT) and maceration (MACR) techniques, the present study aimed to evaluate the amounts of quercetin, gallic acid, rutin, naringin, and caffeic acid in ginger capsules of Z. officinale. High-performance liquid chromatography (HPLC)/ultraviolet was used for separation and quantitation. In vitro toxicity evaluation of ginger capsules on the CRC cell line HT-29 was also conducted to assess the anticancer activity of the supplement. The cell line HT-29 (HTB-38) colorectal adenocarcinoma was utilized for the antiproliferative effect of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. Ginger herbal supplement extract at dosages of 200 and 100 μg had strong cytotoxic effects (IC50 < 50 μg/mL) on HT-29 CRC cells via MACR. This extract is comparable to the SOXT extract, which has an IC50 of less than 50 μg/mL. The anticancer effect of ginger herbal supplement formulations against CRC lines was investigated, and the results obtained from both the MACR and SOXT extraction procedures were noteworthy. The quercetin content was the highest of all the extracts according to the HPLC data.