The boss of Morrisons has said the supermarket was stocking up on "cupboard fillers" in preparation for a potential no-deal Brexit.
However, the supermarket chain would not give any details of which products were involved.
Chief executive David Potts did say there had been a recent rise in sales of painkillers and toilet rolls.
Morrisons is considering alternative routes to import goods if its usual supply lines were delayed, he added.
In the event of a no-deal Brexit there are fears that there could be disruption at ports and Morrisons has also been looking at alternative ports and ways of getting goods into the country.
Sales of painkillers and toilet rolls had risen by high single-digit percentages in recent weeks.
"We have seen a very small amount of customers buying in," said Mr Potts.
Publishing its annual results, Morrisons said there had been "continued uncertainty" about Brexit throughout the year and the chain had come up with contingency plans.
The uncertainties it identified included the impact on the supply chain, imported food inflation, the impact on consumer confidence, potential changes to access to EU labour and changes in legal requirements.
In response, the supermarket has applied for and got Authorised Economic Operator status, which gives firms quicker access to some simplified customs procedures and, in some cases, the right to fast-track shipments through some customer and safety and security procedures.
It said it had also sought alternative supply routes for key products, adapted its labour model and increased stock levels for "certain key lines".
Thomas Brereton, retail analyst at Global Data, said: "With Brexit still looming over the retail sector in 2019, talks of supply shortages and impending lack of availability across UK grocery are rife.
"But Morrisons is better placed to withstand such pressures than its Big Four rivals, having successfully secured Authorised Economic Operator status during the year, on top on expanding its dependence on local suppliers."
Morrisons also announced a third consecutive year of strong sales and profit growth.
It reported an annual underlying pre-tax profit of £406m, up 8.6%.
Like-for-like sales, which strip out stores open for less than a year, were up 4.8%, excluding fuel and VAT.
The retailer said the results showed the Morrisons turnaround plan was "well on track".