Can dogs have catnip?

What do you mean by "have"? -- eat it? Wallow in it?

I'm not sure dogs would be as thrilled by catnip as cats are. Does your dog react to it?

If it's a cat nip toy, there is really no harm, but I wouldn't let him ingest large amounts of it. My dogs have eaten it numerous times, no side effects to mention aside from horrendous diarrhea afterward.