The heat is not enough. The fried cabbage is a bit bitter because the heat is not enough. Cabbage is rich in nutrients. If the cabbage becomes bitter due to low heat or short cooking time, don’t worry. Generally, it can be eaten normally and you can fry it for a while longer. Before frying, I found that the cabbage has gone bad. If it becomes bitter after frying, it cannot be eaten. It may be that the cabbage has been left for too long, causing the cabbage to become stale, losing nutrients or being corroded by mold, thus affecting the taste of the cabbage.