I found my 3 yrs old son medicine (albuterol) that he takes in a nebulizer, its almost three years old. can he still use it?

I wouldn't: Unless it is clearly within the recommended dates for use, it has likely lost strength. I would toss it and contact your doc if you need something for this illness.

See below: Albuterol may be less potent over the expiration date, however, it may still work until your next follow up or refill. The expiration date is actually the predicted date at which the drug will lose 10% of its potency. If stored in proper temp and humidity and not opened-it may have enough potency to get you by for the short term.

Safe, but not work?: He could use it, but after three years it may not be that effective.