Because of the medication I take, I have dry eyes. This makes it especially difficult to wear contac lenses. I have found several products that work for me with my particular condition. This blink lubricating drop is one of the best products that I have found. With one drop, my eyes no longer feel scratchy and dry. I carry this drop with me in my pocket or purse at all times. I am leery of putting things into my eyes but I trust the makers of these drops. Everything possible is utilized to ensure the consumer is protected from tainted products. There is a seal on the cap that must be broken prior to use. I did have an issue with a bottle of these drops. When I unscrewed the lid, the portion under the lid had developed a musty smell. I emailed the company and within 30 minutes, I received a phone call. They provided me with a label to send the bottle back to them and coupons for a new bottle. I appreciate their care and concern and have no doubt they will isolate what went awry with that bottle.