World champion Manny Pacquiao left hospital yesterday following treatment for an ulcer possibly brought on by his campaign for a seat in parliament.

Pacquiao, 31, who was taken to a hospital for stomach pains on Sunday, said he was suffering from an ulcer which may have been caused by irregular eating habits during his recent political campaign.

"I must be disciplined and not miss meals during the proper time," he said.

The 31-year-old fighter, who was elected on May 10 to represent the southern province of Sarangani, has been preparing to take up his post in the Philippine parliament.

Boxing promoters are also working to arrange a bout between Pacquiao and American Floyd Mayweather in November, to settle once and for all the fighters' claim to be the best fighter, pound-for-pound, of their generation.