Spirulina is a cyanobacterium that is around 0.3 mm long and grows in lakes of the warm regions of the planet. The scientific name of dihé is Arthrospira platensis. In Chad, it grows in some very specific ecosystems called ouaddis (oases). These are little stretches of water on the east side of Lake Chad. Dihé is harvested throughout the year, with a small yield in December and January and a larger harvest in the rainy season, between June and September. Only Kanembu women harvest dihé. Men are banned from entering the water under the belief that they would make the lake barren. The harvesting begins in the morning and is supervised by an older woman who is responsible for guarding the lake. The women skim off the blue-green algae that floats on the surface and pour it into their baskets or directly into jars. A single woman can generally harvest 4-8 kg per day. After the harvesting is over, they dig round holes in the sand; the suspension of algae is then carefully poured into the holes. Dihé is obtained by filtering and then sun-drying the algae on the sandy shores of the lake. The semi-dried dihé is then cut into small squares and taken to the villages to finish dring on mats in the sun. When ready for consumption, it is crumbled into a bowl by hand or with a mortar and pestle, cold water is added and mixed in until smooth and then the dihé is cooked for 1-1.5 hours. Dihé is a traditional component of the Kanembou people’s diet and is used in different dishes. It is mainly used to make a traditional sauce, with can be made with beans, dried fish or meat. It is also eaten mixed with rice, milk and oil. Locally, it is also used medicinally to treat wounds, headaches and stomachaches. It is not known for exactly how long dihé has been consumed in Chad. It was first noted by outside observers in 1940. It is likely that it has long been part of the local diet, due to the fact that it grows naturally in the particular ecosystem found in the region of Kanem around Lake Chad. Therefore, it belongs to the culture of the local population who learned how to work with those very particular ecosystems without destroying them, to exploit and preserve them at the same time. Today, besides being consumed locally, dihé represents an importan source of income for Kanembu women, who also sell excess amounts of the product to local consumers or wholesalers who trade in larger markets. Dihé, and the knowledge associated with its harvesting, preservation and cooking, is at risk of extinction however, due to changes in the local environment. Lake Chad is believed to be shrinking, either from drought problems or the growing exploitation of the lake and river for agricultural use, or both. This is also negatively affecting the ouaddis along Lake Chad that are host to the dihé.