Pachana means to digest, burn, or neutralize ama. Pachana is done by using certain herbs and spices, such as trikatu, chitrak, cinnamon, ginger, black pepper, cumin, coriander, and fennel. Pachana substances burn ama directly without the help of agni. They are often the same herbs used for dipana, but they are given in a double or triple dose after meals, to improve the digestive capacity and to eliminate toxins.
Source: ~Vasant Lad