Red Potion is a 2% mercury bromide solution with weak disinfecting effect, suitable for small wounds; Purple Potion is a 1%~2% gentian violet solution with disinfecting and astringent effect, suitable for wounds with exudation. Red potion and purple potion have different compositions, red potion is 2% mercury bromide solution, less irritation to the skin, but disinfection, antibacterial, penetration effect is poor, only suitable for superficial small wounds. When using red potion, you need to pay attention to not large areas of application, not and iodine together, so as not to cause mercury poisoning. Purple potion is 1%~2% gentian violet solution, disinfecting effect is stronger, and has a certain astringent effect, commonly used in the oozing skin, mucous membrane problems, such as chicken pox, burns, eczema, etc. to disinfect and prevent infection. It should be noted that purple potion should not be used for purulent wounds that need to be drained, so as not to affect the healing of the wound. And the purple potion is easy to cause color residue, not to be used on a large area. Both drugs should be taken under medical supervision, do not self-medicate.