Two men from Lawrence Hill, Bristol, have been arrested for drugs supply offences.
On Friday 26 July officers were notified of a package intercepted by UK Border Force containing what was believed to be approximately 4,100 tabs of the LSD drug.
It was estimated to have a street value of £41,000.
Police went to the intended delivery address of the suspected recipient and arrested a 35-year-old man on suspicion of the importation of Class A drugs.
A search of the house also found three large tubs of cannabis believed to be worth around £5,000. The man was also arrested on suspicion of possession with intent to supply class B drugs.
A 39-year-old man was also detained and found to be carrying a large amount of cannabis resin.
Other drugs paraphernalia found included cannabis oil, magic mushrooms and cannabis resin with a believed further street value of more than £10,000.
The 39-year-old was arrested on suspicion of intent to supply Class B drugs.
Both men remain in police custody.