Egyptian medical sources said around 150 protesters were injured while police were dispersing them with tear gas and water hoses on Tuesday night.
Most of the injured were transferred to hospitals.
Protesters shouted anti-government slogans while escaping through the side roads surrounding Tahrir Square where thousands had gathered, according to German news agency DPA.
Eyewitnesses said demonstrators regrouped in front of the the ruling National Democratic Party's headquarters on the Corniche and hurled stones at the building, smashing glass.
