I have been getting phlegm while working out at the gym. i almost throw up.over-the-counter meds don't work. i drink over a gallon of water a day.

Consider acid reflux: Acid reflux can cause a sensation of phlegm. Minimize caffeine before exercise. Drink plenty of water during your workout. Reduce breath-holding during your work out. Avoid foods that cause reflux before exercising. You could try an OTC acid blocker to see if this helps. Post-nasal drip can also cause phlegm. If I can help, then join my care team & virtual practice at healthtap.com/dr-clarkeholmes