What killed grandma?
If you find a death certificate for great-great-grandma and it lists the cause of death as "Hectical Complaint," you probably will ask, "What's that?"
Yes, I had to look that up. Luckily, there is a one-page "dictionary" on USGenNet that can be a very useful tool for any genealogist who is reading old documents. It shows old medical terminology and then shows the modern-day name for each.
You can find Old Disease Names Frequently found on Death Certificates at http://www.usgennet.org/usa/ar/county/greene/olddiseases1.htm.
My thanks to Pierre Clouthier of Progeny Genealogy Inc. for pointing to that page.