About Aphthous Ulcer: These small sensitive painful craters in the mouth are common canker sores. There are many possible causes of apthous ulcers and frequently the cause is unknown. See also: sub-topics
The IRS phone number for individuals is (800) 829-1040. Businesses can call (800) 829-4933. Hearing impaired individuals can contact the IRS using TDD at (800) 829-4059. Operating hours are between 7 a.m. and 10 p.m. in your local time zone. After hours, a recording will direct you. Have all your paperwork in front of you when you call.
How to Contact the IRS By IRS Customer Service Numbers Individual telephone assistance can be obtained by dialing 1-800-829-1040 Monday through Friday from 7 AM to 7 PM.