HELP!! Kitten diarreah

I recently took in 2 Foster cats, a Mama (approx. 1.5yrs old) and her baby who's about 3mos old now, and after about 2 weeks discovered they had round worms, the rescue I'm dealing with has not been very helpful so needless to say it's been rough...but I finally got meds from them and was told to dose them 3 times, 10 days apart. I have given them 2 doses so far and I'm supposed to give them the 3rd this friday, but I've noticed that the kitten has had bad diarreah the past couple of days and his anal area is red and maybe a little swollen...I've been cleaning it and keeping an eye on him but he's eating, drinking and playing as usual, so I'm not sure if I should be overly concerned or if maybe it's just because of the dewormer...I have 2 cats of my own besides the fosters and everyone else seems to be fine. I'm worried because he's so young that maybe he got into something that I'm not aware of or something and maybe ate something he shouldn't have but it's been about 3 days now and since I haven't had much luck dealing with the rescue that I got them from I'd rather handle it on my own instead of calling them as they're not much help anyways...I'm just worried about my baby...and yes, incase you're wondering, I'm a foster fail, I'm keeping the baby but hoping to find a home for the mama soon as 4 cats are just too much but I'd like to get everyone healthy before we do that. The good news is, I haven't seen any worms since the last dose so I think we're over that, I'm just wondering if this is a side effect or something as it's my first time ever having cats with worms...Any advice or ideas on how to firm up his poop?

Im sorry, I can't really give a long, great advice for whats going on with the kitten, but I can tell you what worked when my kitten had diarreah. I boiled some patatoes and made them into mashed patatoes, without anything in them...he would eat just a bit but that always helped him. You can try it and see if it works.

Hi and welcome to the cat site, 

I am sorry your kitten is sick! You may get more answers in the pregnant cat and kitten forum (http://www.thecatsite.com/f/36/pregnant-cats-and-kitten-care). 

Some useful tips on dealing with stool issues is to feed a bland diet. Most people have success with feeding just boiled chicken for a few days. Canned pumpkin (not the pie crust filling) is also useful. Probiotics are also sometimes helpful. I would not advise to feed potatoes imo. 

Because kittens can go downhill quickly it is best to contact a vet and see what they think. He may have coccidia which can be treated with antibiotics or certain probiotic blends. Here is a recent thread on a kitten who has it (http://www.thecatsite.com/t/262945/dark-brown-eye-crust-in-corners-of-eyes). 

Thanks so much for your advice. I finally got someone at the rescue to help me get him to a vet, they say it's a side effect from the dewormer and the worms leaving and such, but they gave me flagyl to give him and some bland wet food. I will continue keeping an eye on him, but I was worried there was a chance it could have been coccidia too. Thanks so much for your concern and advice, love this site!! =)