"deadly dose" is correct and usable in written English.
You could use it to describe a lethal or fatal amount of a substance such as a drug, medicine, or poison. For example, "The patient was given a deadly dose of the same medication that had resulted in an overdose in others."
Eight mice were infected with a deadly dose of 110 million streptococci bacteria.
Opening the bottle at arm's length would be enough to protect the killer from receiving a deadly dose.
When Michael Lee Wilson received a deadly dose of pentobarbital in Oklahoma in January, he responded with the now-notorious cry: "I feel my whole body burning".
The Idec Pharmaceuticals Corporation won approval today for Zevalin, its treatment for non-Hodgkin's lymphoma, the first of a new class of drug that zeroes in on cancer cells and zaps them with a deadly dose of radiation.
"We have to continue on this course," she told a rally in Berlin, denouncing the European policies of her main rival, Peer Steinbrück, who had called for a presumably mostly German-financed Marshall Plan to relieve what he called "a deadly dose of austerity".
Taking grudge-holding to new depths, Updyke/Al claimed on the call to have infected the landmark trees with a deadly dose of the herbicide Spike 80DF in retribution for Auburn devotees' supposed toilet-papering of the oak trees in celebration of Bryant's death 28 years ago.
How organisms survived these mutations piqued the interest of Sancar who noticed that bacteria exposed to deadly doses of UV could repair themselves if lit up blue light.
The question of what will happen next — whether Hamm will be allowed to die of natural causes in prison, or will be tied down to a table one day and injected with deadly doses of drugs — lingers on the edge of every conversation he has with his attorney.
It may not work against Godzilla, but a new drug could protect people from deadly doses of radiation.
As governor of Delaware, if I had eliminated every source of air pollution within my state, stopped every combustion source, and ordered every motor vehicle off the roads, Delaware would still have faced deadly doses of air pollution".
An unprotected person standing close to the contaminated areas would, within hours, receive a deadly radiation dose.
