Pros: Great antiseptic, really does help heal faster with less scarring
Cons: Allergic reactions
Neosporin is the megastar of all antibiotic ointments. Everyone has heard of it and nearly everyone has used it. It does work as advertised and is a great product, but with one fairly significant drawback.
First, the good: The combination of three antibiotics (Neomycin, Polymyxin, and Bacitracin) in this and in generic 'Triple Antibiotic' are deadly to the bacteria that most commonly infect cuts, scrapes and scratches. The petroleum base keeps wounds from drying out. This is good. Most of us were taught to let a crust (scab) form on a wound. This does keep it from oozing and thus makes it less messy, but the crust also slows healing and increases scarring. Minor wounds heal by the migration of surface skin cells from intact skin to the damaged area. When a crust forms, the cells cannot migrate-thus slower healing and more chance for abnormal healing (scarring.)
Second, the bad: Neomycin, one of the three antibiotics used in Neosporin causes an allergic skin reaction in around 20% (some dermatologists say it's closer to 25%) of people who use it repeatedly. The reaction is usually mild and resolves when the medicine is stopped, but I have had many patients who interpreted the red skin from an allergic reaction to be infection, so they keep applying the Neosporin (or Triple Antibiotic.) They are confused when the redness worsens, and I can't blame them, I've seen it a lot and can't always tell for certain if it's allergy or infection. Because of the reaction, there are a number of clinics and emergency rooms that no longer use or dispense Neomycin containing products.
There are great antibiotic ointments that help healing just as well that contain one or both of the other two antibiotics and don't cause the allergic reaction. Polysporin and Bacitracin are the most common brands, but the generics of these are as good and, or course, less expensive. Confused what's in the ointment you're buying, read the ingredients label!
Conclusion: Neosporin and Triple Antibiotic ointment/cream are great products and work well and I recommend them, but be aware of the possibility of an allergic reaction. Use an ointment without Neomycin if there is any doubt or concern of possible reactions.