Why it matters: The acquisition represents Amazon's biggest move yet into the healthcare sector and threatens the traditional retail pharmacy model in a major way.

Amazon on Thursday said it is buying online pharmacy PillPack for an undisclosed sum. The company had previously been linked to a potential deal with Walmart for under $1 billion according to CNBC.

PillPack strives to provide the best possible customer experience for people in the US who take multiple daily prescriptions. The company delivers medications in pre-sorted dose packaging, lifting the burden of sorting doses and scheduling for patients.

Anyone who takes multiple daily medications is likely well aware of the hassle (and risk) associated with trying to remember whether or not you took a certain pill. Skipping a dose can be just as bad as taking an extra pill, fears that PillPack should seemingly eliminate.

The online pharmacy also coordinates refills and ships prescriptions to customers' homes.

PillPack holds pharmacy licenses in all 50 states, has URAC and VIPPS accreditation and is an in-network pharmacy with most PBMs including major Medicare Part D plans.

Leading drugstore chains are already feeling the effects of Amazon's deal. In early morning trading, CVS Health Group shares are down 8.75 percent. Walgreens Boots Alliance is down 8.76 percent as of writing and Rite Aid Corporation slipped 11.17 percent.

The deal is expected to close during the second half of 2018 and is subject to customary closing conditions.