My Tea Cup Chihuahua barks and goes crazy almost biting female guests?

Google "Small Dog Syndrome". There's a reason chihuahuas are known as little monsters. It's easy to forget that, though small and cute and generally harmless, they are still dogs and if untrained and unsocialized they will act just like a pit bull or great dane or german shepherd or lab that has been untrained and unsocialized, often resulting in fear, possessive behavior, or aggression.

Next, google Nilif Training and start over on basic obedience. When company comes over keep a little baggy of treats near the door so they can offer the dog a little something when they come over. It'll desensitize him to their presence and teach him that the family friends are fun to have around.

[Add] I hate to say it, but the "runt of the litter" comment was more or less accurate. There is no such thing as a teacup chihuahua, the breed standard simply states that any chihuahua under 6 lbs is acceptable. If yours is over 6 lbs it's not only not "tea cup", it's not even small enough to fit the breed standard. "Tea cup" is a gimmick used by unreputable breeders to get you to pay more for their dogs. These same breeders rarely, if ever, scrutinize their pedigrees for temperamental or physical defects nor do they properly screen the dogs they breed. In the case of poorly bred dogs, sometimes it really is just a bad temperament. Alaskan Huskies are often skittish, neurotic little things because some breeders breed them for function with no regard to temperament. A genetic temperament defect can't be fixed with training. It's more likely a training issue with you, but be aware that it may not be.

You bought a poorly bred runt, there is no such thing as a tea cup anything. These "tea cups" usually have behavioral problems and other issues, such as not know how to use to toilet outside. Not only your dog but most poorly bred dogs have issues like that.

What you do is when a female guest comes in is have a baggies of treats by the door and they give him one and walk on. If he shows any aggressive behavior remove him from the room and leave him in the bathroom for about 3 minutes and bring him back. If he growls, barks, or snaps remove him again. He will understand that if he acts this way he is left alone.

You have a 6 month old chihuahua with a bad temperament, nothing else. If your dog fits in a teacup at 6 months, I'll take this back and offer you a public apology. I'd suggest taking him to a training class before the problem gets more out of hand

It can take a while but you can train your chihuahua to stop barking and going crazy when people visit.

Thats funny, because i have a female teacup chihuahua who is about 3 years old, and every time my aunt or my best friend(female) come over, she bites at their ankles and becomes the attack dog! strange! i wish i had answers too :P (she doesnt do that to anyone else) P.S. mine was the only puppy in her litter and she does the same thing. chihuahuas are naturally protective. i just wonder why only specific people affect their behavior

Socialize him more often. A training class will also help.

You have a runt of a litter. They come with medical and psychological issues. (agression included).

Mine is one year july and she does it to everyone except me.