Can you take Penicillin and NyQuil at same time?

Yes, I believe you can. NyQuil treats your symptoms the same way a regular cough medication would. It is not the same as Penicillin and should not interfere with the antibiotic. Often doctors recommend taking something to help your symptoms while on an antibiotic, NyQuil is the same. It isn't good to take NyQuil or any other cold medication for several days in a row though, you should always read the label to see how many days it is recommended to take.