What is Hashish? Hashish is a cannabinoid, like marijuana. It consists of the THC-rich resinous material of the cannabis plant, which is collected, dried, and then compressed into a variety of forms, such as balls, cakes, or cookie-like sheets. The Middle East, North Africa, and Pakistan/Afghanistan are the main sources of hashish. The THC content of hashish that reached the United States, where demand is limited, averaged 6 percent in the 1990s.