On Thursday 19 May, Red Shirt protestors are expected to hold a large-scale demonstration from 13:00 until 23:00 in the central shopping district of Ratchaprasong. This is likely to cause major disruption to traffic in the area.
Anti-government demonstrations have been taking place in Bangkok around the 10th and 19th of every month at the Democracy Monument (near Khao San Road).
You should avoid this demonstration and any other protests.
For further information, please see our travel advice for Thailand.