The government has awarded £86.6m of contracts to ferry companies to transport medicines in the event of a no-deal Brexit.
Brittany Ferries, DFDS, P&O and Stena Line will be able to deliver those supplies from 31 October, it said.
The contracts are aimed at making sure deliveries of vital products continue, if the UK leaves the EU without a deal.
The government was criticised earlier this year after awarding a transport contract to a company with no ferries.
The contracts will be in place for six months.
Transport Secretary Grant Shapps said: “The UK is getting ready to leave the EU on the 31 October and, like any sensible government, we are preparing for all outcomes.
“Our decisive action means freight operators will be ready and waiting to transport vital medicines into the country from the moment we leave.”
The firms will operate on routes away from the busiest ports to minimise disruption, the Department for Transport said.
The UK ports the ferries run to will be Teesport, Hull, Killingholme, Felixstowe, Harwich, Tilbury, Portsmouth and Poole.
Earlier this week, the government established a customs paperwork support unit for medical goods suppliers to help with getting across borders in the event of a no-deal Brexit.