Ten people were injured in Russell Square in Dhaka, the capital, as police confronted rock-throwing activists attacking vehicles.
About 40 others were hurt in similar violence in the northern Patgram area, local officials said. Police detained an unspecified number of activists in Dhaka and elsewhere.
A 14-party alliance led by Sheikh Hasina, the Awami League leader and a former prime minister, called the latest strike as part of its campaign to force the government to implement electoral reforms before parliamentary polls due in January.
Schools were closed but most offices and banks were open. Streets were crammed with rickshaws and cabs. Trading on the country's two stocks exchanges in Dhaka and Chittagong was suspended.
Abdul Mannan Bhuiyan, secretary-general of the ruling Bangladesh Nationalist Party, accused the opposition of trying to cause chaos through a long series of strikes and vowed not to give in.
Abdul Jalil, Awami’s general secretary, said: "We have no other language instead of strikes to express our protest against this repressive government."