The eight Cord and Jubilee MPs who were detained on Tuesday over hate speech are complaining of cold, flu and chest pains.
Lawyers John Khaminwa and Harun Ndubi have moved to court to seek orders to have the MPs at Pangani Police Station taken to hospital for check-up.
The MPs held are: Machakos Senator Johnson Muthama, Ferdinand Waititu (Kabete), MPs Junet Mohamed (Suna East), Timothy Bosire (Kitutu Masaba), Moses Kuria (Gatundu South) and Kimani Ngunjiri of Bahati.
Women representatives Florence Mutua (Busia) and Aisha Jumwa (Kilifi) are also in police custody.
Police officers at the station declined to allow other leaders to see the detained MPs.
The Hight Court on Wednesday rejected an application seeking to release the accused lawmakers on bail.
Their case is scheduled for hearing on Friday.