Forensic Toxicology Valentines

Happy Valentine's Day!

Here are a few Valentine's wishes.

Roses are CO red.
Violets are cyanotic blue.
Let's hope you're neither already dead,
Nor hypoxic too.

Postmortem blood is red.
And sometimes blue,
And oftentimes green.
And maybe black too.

Decomposed liver is brown.
Decomposed liver is too.
Decomposed kidney is also brown.
Why is everything brown?

Postmortem blood is red.
It may also be blue,
Though it can be black.
It smells horrible, too.

MDMA and cannabis are Schedule I.
LSD is too.
Do they belong?
Let me ask you.