The main ingredients of the patch are salicylic acid and phenol. People who are allergic or intolerant to these two substances should avoid using the patch. Salicylic acid has the effect of dissolving keratin, and phenol can be sterilized and has a certain corrosive effect on the skin. The correct order of use, such as cleaning the keratin, paste corns and change the medication on time, in order to reduce unnecessary damage while treating the disease. 1, clean up the keratin: first soak the foot with hot water for 10 minutes to soften the keratin, so that the corns can be well fixed, conducive to drug penetration, pay attention to the water temperature is not too high, so as not to burn the skin. If the foot skin keratin is thick, you can extend the soaking time or use exfoliating products, and then gently scrape the foot surface has been softened keratin, dry the foot moisture, keep the local clean and dry; 2, paste corns: open the package, the corns paste in the affected area, pay attention to the scope of the corns paste to accurately cover the location of the corns. If the scope of the corns is smaller than the corns patch, you need to protect the normal skin around the corns to avoid corrosion by the drug, you can put a small cotton ball on the normal skin pad or paste medical sterile tape; 3, change the medication on time: 24 hours later, if the affected skin color is white and slightly painful, you can remove the whitened skin first, clean the residual drug on the foot, and then paste a new corns patch. If there is no such phenomenon, the paste can be extended appropriately for 3-5 days for replacement, and each replacement needs to be thoroughly cleaned and the corns pulled out. If the corns are more serious, several consecutive courses of treatment may be required until the corns fall off. It is important to note that corns are not to be used on broken skin. If there is burning sensation, itching and redness in the area where the medication is used, the corns should be discontinued immediately and the medication should be rinsed off.