Pinched Medicine Bottle ?

[dumpicker]

This bottle is 4.5 inches tall but only holds one ounce of liquid. You can see from the bottom that this bottle is almost all glass. Mold seams are on the diagonal

 

[East_Tn_Bottle_Guy]

It's not uncommon for medicine or extract bottles to do that, and I believe yours is an extract. I'm not sure what causes it to be so thin in the middle though if that's your question. And if that's the case sorry I wasn't any more help.
For example, here's another that does it

It's six inches tall.

 

[CanadianBottles]

I agree on it being an extract, designed to make the bottle look as large as possible without actually containing very much of what would have been a pretty expensive product used in small amounts.

 

[PlaneDiggerCam]

I agree on it being an extract, designed to make the bottle look as large as possible without actually containing very much of what would have been a pretty expensive product used in small amounts.

Yup most extracts usually have a simmilar shape to this, however I have seen these type of bottles used for medicine too.