Emergency services were called to the incident on London Road at 11.30am following the collision, which involved a Renault Captur and a Vauxhall Astra.
The A16 was closed in both directions after the incident.
Three people have been taken to hospital with injuries which are described as non-life threatening.
The 29-year-old driver of the Vaxuhall Astra has been arrested on suspicion of driving while under the influence of a controlled drug.
Anyone with any information should call 101, quoting Incident 143 of 28 September.