This article is from the the official alt.spleen FAQ, by Andrew Stellman with numerous contributions by others.
Andrew says: NOTE: PLEASE DO NOT SEND ANY MAIL TO ME REQUESTING MEDICAL ADVICE! I AM NOT A DOCTOR, AND WILL NOT GIVE YOU ANY USEFUL INFORMATION.
M. R. Austin (M.R.Austin@bradford.ac.uk) seems to have hit on the answer:
"I have discovered why Margaret Thatcher fell from power. She had a spleenectomy in 1991. AND she didn't use the sacred word of Spleenage, that I shall impart to you spleen lovers. Say this often to help your spleen. 'Boogaloo!'"