After reading several reviews for this product, some customers were complaining about a bad odor from this product. It is an odor to say the least, but the odor smells exactly like what the product is. It smells like what 100 gallons of fresh salmon oil would smell like. It is strong. if it was to expire, you would definitely know it. My dog has improved by leaps and bounds with itch %26 allergy relief. I started her on one squirt from the bottle. Now with 3 squirts per meal, she is licking her bowl clean every day. And now taking her to the vet is out of the question. This product is saving me hundreds if not thousands of dollars avoiding vet bills.