The plume of ash from Mount Bulusan in the rural eastern province of Sorsogon went two kilometres into the air, the Philippine Institute of Volcanology and Seismology said in an advisory.
Institute head Renato Solidum said nobody was living within a four-kilometre danger zone near the volcano, but that people in nearby communities should wear masks outside or stay indoors.
Solidum said that inhaling the ash could cause difficulty in breathing and respiratory illnesses.
Bulusan has had nine similar explosions since May last year. Solidum said today's lasted for about 30 minutes, and that more could be expected.