Why does Keflex smell bad?

Yes. It is one of the "smellier" drugs. This class of antibiotic is based on a chemical found in a fungus discovered in a sewer in Sardinia. That isn't the reason that they smell, but it is not surprising based on the history of the medicine.

Yes

Hi rose, it does indeed have an odor!! I have a feeling it's the "other inactive ingredients" that give off this smell.

"Each capsule contains cephalexin monohydrate equivalent to 250 mg, 333 mg, 500 mg or 750 mg of cephalexin. The capsules also contain cellulose, D & C Yellow No. 10, F D & C Blue No. 1, F D & C Yellow No. 6, gelatin, magnesium stearate, silicone, titanium dioxide, and other inactive ingredients"

It's considered a sulfa which is what causes the rotten egg smell

It must be the medicine itself ... the excipients shouldn't smell.