When the foot patch is used up, it is usually black or yellow, mainly the color of the foot powder package. Of course there are other colors, but most of them are physical phenomena.

1, black or other colored liquid will be discharged during the use of the foot patch, which is usually a physical phenomenon. This discoloration phenomenon is just like the usual material bag cook the meat, which is filled with black material. Once it is put into water, it will turn black.

2. Hair oil is mainly due to the reaction between sweat on the soles of feet and foot powder. Similar to oily products in cosmetics, powder is not easily absorbed, but oily is easily absorbed.

3. If the foot patch does not change color or drain oil after use, the main reason is that the patch is not firm or there is no sweat on the soles of the feet. It is recommended to stick it firmly after soaking in hot water. Use the foot patch reasonably, and don't be superstitious, so as not to cause a psychological gap and take it out on the foot patch.