How much does she actuallly weigh? What, how much and how often are you feeding her? How active is she? Has she been dewormed several times and with what medication (was it given to you by the vet, or did you buy it at the store yourself)? Is her poop normal in color and consistancy? Worms, digestive enzyme deficiencies, poor food quality, higher than normal caloric needs due to illness/ rapid growth/high levels of activity are all possible reasons for poor body condition. Since you are asking about fleas as well, a heavy infection with tapeworms may also be the culprit. Under normal conditions tapeworms are not a health problem (they are just gross!),but in a very young rapidly growing kitten with high activity levels that probably didn't get any immunity from it's mother's first milk, they could be a problem. Flea remedies generally involve pesticides. I use Frontline spray monthly because I can use it on my dogs and my cats, but they make a spot on product too. The most important thing about treating fleas is to treat the house and yard as well as the pet because for every flea on the animal there are 9 more eggs/larvae ready to develope into a flea very soon!! Vaccuum everything thoroughly (floors, carpets, furniture, etc) especially where the cat sleeps and spends the most time, this causes the eggs to hatch into larva so they will be killed by the pesticides. Wash any sheets, throw rugs, blankets, cat bed, etc in the hottest water you can use to kill any eggs or larvae. Then set off bombs in the house making sure to follow product instructions. While treating the house, take the cat out and give it a flea bath and treat it with whatever product you choose. NOTE: Depending on the flea product you use they may advise against bathing prior to application, this is the case with Frontline products! Regarding natural flea treatments the only one I know of is really best used for maintenance, rather than treatment. A daily combing with a good (read: closely set teeth) flea comb, dipping it in slightly sudsy water (add 1-2 drops of flea shampoo to a small bowl of water) is the only one I know. Don't use dish detergent, people shampoo or body wash in the water because they are not formulated to the correct ph for animals and they are not meant to stay on the skin/hair without causing irritation. Hope this helps with the fleas. post back answers to the "weight" questions and maybe we can narrow down a plan for getting some weight on your kitty.