Yes, there are many people who have used/are using alli with one or both of these condition and have done very well! The alli label is very specific that anyone with diabetes or gallbladder disease (that includes removal) speak with their physician before starting alli.
If you've had a problem losing weight that's something to check with your doctor as well. There may be an underlying medical issue that's causing it.
Please let me know if you need anything else.
Pat Baird, MA, RD, registered dietitian