Need to gain pounds quick but build muscle. How?

Gaining weight fast is the same as loosing fast....it's not a good idea health wise. Unfortunately you need some patience with the process. I too had lost a lot of weight from health related problems, a few years ago. I used weigh protein to help build back muscle, you can find it at GNC or even Sam's Club. Also going to the dr. and getting a blood test to see what you body lacks, nutrition wise will help. Remember all the vitamins your body utilize work together to build muscle and burn fat as well as properly maintain necessary fat deposits. So see what your lacking before you try and add things to your diet. Don't binge on fatty or high calorie foods just to gain weight unless your dr. gives the o.k. It wouldn't hurt to evaluate your eating habits and maybe adding some natural fats to your diet rather than junk food could help. But definitely high protein food and weigh protein help to build muscle in an adequate amount of time.