"i bought the dap dispenser originally to stop kylie from barking when i went to work. she originally barked her head of for 2-3 hours total during the day. the first vial didn't really seem to have much effect on that, but 5 weeks later, on my second vial and with a spray collar, she's doing really well.
disclaimer: the improvement may not necessarily be due to the dap, at best it is probably due to the combination of her getting used to my new apartment, getting sprayed with the collar (only works on her loud barks, not her crying or howling), and possibly the effect of the dap. however, i've read too many "miracle" stories to completely discount the effect."