For about 2 years, a medical problem has more or less repeated, as follows:

The problem normally lasts approximately 3 weeks and then goes away for 3 or 4 days and then repeats.

When eating a non-conventional food item, the problem goes away in approximately 2 days instead of 3 weeks. The problem will then return as usual in 3 or 4 days.

This non-conventional food item has worked 4 times thus far in stopping the problem in approximately 2 days. One of the 4 occurrences goes back about 3 months. The other 3 occurrences are more recent. These were the only 4 times it was tried.

What is the approximate probability of there being a valid correlation of this non-conventional treatment and the improved result?

Also, if it works 5, 6, 7 times, etc. what would the probability?

Thanks in advance.