If you've had any history of asthma past age 13, you're done! Now if you're already in the military and are diagnosed with asthma, depending on the the severity, will determine if they want to keep you in. I had a reaction to the antrax vaccine and had was diagnosed with mild persistant asthma. I couldn't deploy due to having to remain close to a major military medical facility. Luckily I was on shore duty, so I was able to prolong my time in the Navy. They tried all sorts of medication. I felt like a guniea pig for Navy pulomonary science. They were just trying to find a way to get it under control and get me back to fulll duty. Didn't happen so I was medically discarged.