Board Thread:Off Topic/@comment-25396609-20190908002326/@comment-25396609-20191222183141

First thing you need to do is pick one type of disease; limit the scope of the ability before the scale

As it stands your viable options are:

Physiological diseases; things caused by some inherent defect of the host body. Cancer, arthritis, glaucoma, macular degeneration, etc

Infectious diseases: things cause by harmful microorganisms; viruses, bacteria, fungi, and such. Ranges from the common cold to pneumonia and even AIDS.

Assorted poisonings: separating these out since they're not necesarrily a kind of disease, but purging toxins such as heavy metals, carcinogens, and organic venom/poison compounds would also be a good Semblance.

After deciding what grouping of ailment the Semblance would be able to treat, THEN you can work out how many can be treated per use, and establish any limits on how many times it can be used on any given individual.