My dog has been scatching at her ear and crying and it smells real bad. Could she have an ear infection? It happened after she was groomed.

Was she also shampooed at the groomer? Could be water/soap got into the ear and has caused an infection. Clean the ear with mineral oil and a Q tip as best you can. See a vet for an antibiotic ear drops

I know there is some controversy over the use of diluted white vinegar to clean ears, but it is an old fashioned remedy that I find works well. Use 3 parts vinegar to 1 part water. Warm it up a bit, put some into the dog's ear. Rub the ear (you will hear a squishy sound and that's good) then let the dog shake her head. After she does that, get cotton balls and clean the dogs ear. Start inside up to your first knuckle keeping the pressure to the outsides of the ear. Then use more cotton and clean the outer areas. After you are all done, put some mineral oil (if you have a drop each of tea tree oil, chamomile oil and/or lavender oil availablt to put in it, that would help too). Again, rub the ear thoroughly. Do both ears, just in case. Try to do this 2 or 3 times a day for 3 or 4 days minimum, even if symptoms disappear.

I find the various oils help loosen the fungus & bacteria plus the olive oil helps dilute the more healing oils so they aren't too harsh for the ear then they act as natural antiviral, antiseptic and antibacterial agents. Use about 1 tablespoon of olive oil with one drop of as many of the other oils that you have or can get. As far as the white vinegar goes it is my belief that it helps start the correct process back up to fight bacterial infection.

If the ear doesn't seem a lot better in a day or two you definitely should take her to the vet. Ear infections can cause permanent damage.

Hope this helps!

Hugs, Didi

Vinegar and water is a decent treatment for both yeast and bacterial infections, as they often come in when the acidity of the ear canal is lowered. (antibiotics are a better choice for bacterial problems, but yeast doesn't respond to antibiotics.)
There may be ear mites involved, too. Usually there is a dark brown to black 'waxy' buildup, too. Get some dark debris on a Q-tip and look for SMALL tick like looking bugs crawling slowly on the debris. Easy to kill, and easy to catch again, although they don't live much more than a day or two off the animal.

Yellowish discharge is more a sign of a bacterial infection. Probably best for a vet visit if this is the case, however.