Roy Hodgson may not be a fan of anti-malaria tablets, but he insists he has no option but to issue the pills to his players despite the potentially-damaging side-effects.
England head to the jungle city of Manaus on Thursday ahead of their World Cup opener against Italy 48 hours later.
England's players all took anti-malaria tablets Malarone on Tuesday morning at breakfast.
Generally, one in 10 people experience side-effects like stomach cramps, sickness and dizziness after taking the pills.
The last thing Hodgson wants is to lose one of his players to illness, but the England manager has been left with no option but to issue the anti-malarials to his players.
He said: "As far as I'm concerned, I've got to go with medical opinion and if the doctors are telling me that when we go to Manaus the players must take malaria tablets, whether it has side-effects or not, what do I do?
"I can't turn around and say 'we will not take malaria tablets", because the bottom line is better stomach cramps or whatever it is for one player in 10 than have someone contract malaria because that would be unthinkable."
Interestingly Hodgson did not take any anti-malaria drugs before a trip to Manaus last year, but the Football Association has confirmed he will do so this time around.
"I went to Manaus and I didn't take any for the two days I spent there," he said.
"That might just be something to do with the fact that I'm not a football player."
After consulting FIFA's chief medical officer, Professor Dr. Jiri Dvorak, England have decided not to have their yellow fever jabs.
When England land in Manaus they will be fully confident of beating Italy.
Hodgson has been impressed with what he has seen from his players during the first two days of preparation at their Urca military base in Rio.
Hodgson reported on Tuesday that captain Steven Gerrard will be fit to take on the Italians despite a minor groin problem, and there are no fresh injury concerns for the England boss, who has virtually selected his team for the match.