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.
Businesses can contact the Internal Revenue Service on its Telephone Assistance for Businesses at 800-829-4933. The phone line's hours of operation are Monday to Friday, 7:00 a.m. to 7:00 p.m local time. People who believe they may be a victim of identity theft can call 800-908-4490 for automated and live assistance.  A separate phone number exists for Exempt Organizations, Retirement Plan Administrators, and Government Entities: 877-829-5500. The phone line's hours of operation are Monday to Friday, 8:00 a.m. to 5:00 p.m local time. People with hearing impairments can call 800-829-4059 (TDD).