When you use the phrase ‘Sick as a Dog’ you mean that someone is very sick.
Example of use: “How are you?” Answer: “Not great. In fact, I’ve been sick as a dog for the last
three days.”
Interesting fact about Sick as a Dog
The origin of the phrase ‘sick as a dog’ can be found in the early 1700's, when it was common to compare undesirable things to dogs. The explanation for this isn't that people didn't like dogs, it is that diseases such as the plague were often spread via animals like rats, birds, and unfortunately, dogs.
