If your sisiter has tried the over the counter type remedies, she should see a podiatrist (chiropodist) who can cut or freeze it. Both procedures are a bit uncomfortable, neither is actually too bad.
I agree with Woofgang. Freezing them off is the best way in my opinion.. The other creams etc take a fair while to work and it's all a bit of a palaver. Freezing takes only a few seconds and aonly a little uncomfortable while they do it. Tell your sister to see her GP, who may freeeze it off there and then.
Actually, as any decent chiropodist will tell you if he/she doesn't want to waste your money, there is no cure for the verucca. My chiropodist told me to put up with it, and that one day, when the virus has gone, the verucca will disappear.
I'll go along with that. As a long-term sufferer, there are three methods that work. If you don't use them you will wake up one day with hundreds of new ones as that's what they do if you leave them.
The old way was salicylic acid plasters and a wart knife. This took 2 weeks of applications and was 100% effective, so they stopped making it...
Liquid nitrogen works after 1 to 3 applications and has no side effects to worry about.
Finally, a black seed that is ground into water in Chinese herbalists will remove most skin growths in a couple of weeks. Unfortunately very few use it so I doubt it can be found, but I added it as it shows there are other methods that work.
SusieEllen's chiropodist doesn't too competent - sounds like a mechanic who refuses to mend cars (mind I've met some of them in my time). My GP wasn't much better - he gave me a handful of scalpal blades to trim them down with. It did work though, I cut over 20 of them out and was completely clear after a week or two. Still not sure I would advise doing this unless you have exhausted all other methods and have a very steady hand.
I took my daughter to the doctor with a verucca and she told me to use banana skin. Basically put the skin with the inside against the verucca on at night, secured with a sticking plaster. Take it off in the morning and repeat each night. I found it took a week for my daughters verucca to literally drop off!! Sounds wierd, but it really worked. Its cheap and you can eat the bananas!!! Good luck