I have a cat that's almost six months old and she really needs a bath. She's allowed to go outside so she sometimes comes back inside dirty.
Are there any problems relating to bathing her that I should know about? Do I need to use a special kind of shampoo when I bath her?
So, in general I would avoid bathing a cat unless there's a real strong need to do so. The only time I've ever really needed to do that was for fleas, the cat was unable to groom, or the cat got into something that it can't clean off itself.
However, should there be a real need, I would normally avoid shampoos intended for human use. These are formulated to deal with human hair and skin conditions, not feline, and so I would strongly recommend that you use ones formulated for cats since they will be safer. As mentioned in the comments, there are shampoos available for this purpose if needed and you'd be best to find them in pet stores or grooming centres.
The ASPCA has a good article on bathing your cat.
Keep in mind that cats are licking themselves a lot. You wouldn't want to put anything on their fur that you don't want them to consume in small quantities.
I am using a hypoallergenic, liquid PH 5.5 skin care soap in the rare cases where I want to properly clean our cats. (I rarely need to, they are indoor cats, but sometimes I enjoy the super soft fur to be honest) I even tested the product beforehand in my mouth (whether it would burn for example).
There are special shampoos for animals available at every pet shop. I wouldn't use human hair shampoo or conditioners on cats: Those kind of products are often deliberately made to stay in your hair even after intensively flushing them.
I have trained our cats from the get go to accept and enjoy the bathtub. As soon as the kittens started bonding with me and weren't fearful of the environment anymore I put them in the tub at least every second day. It's mandatory to make sure the environmental temperature is very high: The evaporating water in their fur would freeze them: Imagine running around in completely soaked clothes. Now, they sometimes stay in the empty tub and scream for me to start the water.
You should be aware that cats might start to urinate in warm water!
Don't use regular shampoo -- cats have very sensitive skin and regular shampoo will dry it out and irritate it. Most big pet stores will have special cat shampoo available. As an alternative, I have personally had good luck with cat "shampoo wipes." They're basically a wet wipe for washing your cat. They're much easier to use, since you don't have to worry about getting your cat to accept the fact that it's being put in water. I've seen these wipes at big pet stores, and I've bought them before at petsmart.
In a pinch, I've heard baby shampoo is gentle enough for sensitive cat skin, but I wouldn't recommend using it regularly.
