How long can you give a baby gripe water and is it dangerous?

Doubt any harm. A variety of items have been offered to qwell fussy babys since the 1700's, most implying some sort of stomach upset as the cause. A variety of gripe waters are available, some monitored by the fda and some not. Most appear to have harmless ingredients & in small amounts are probably fine. I have never recomended them.If i did it would be one monitored by the fda.
For as long. Dangerous if it has alcohol in it.On the bottle it says good for 14 days. It does not say how long to use it.May i ask what you are using it for - cokic or reflux?