Household products giant Reckitt Benckiser has said last month's malware cyber-attack could lead to a permanent loss of revenue.
The attack disrupted manufacturing and ordering systems at the company, whose products include Nurofen and Dettol.
Although it had "largely contained" the attack, Reckitt said the disruption meant like-for-like revenue growth in the second quarter would be down 2%.
It also said it expected to lose "some further revenue permanently".
The cyber-attack, thought to have begun in Ukraine, spread across 60 countries. It is still not clear what caused it and nor are the reasons for the attack known.
Although ransom money was demanded by the attackers, some experts think the motive may not have been money but access to data, possibly to destroy it rather than use the information for other purposes.
Other large companies affected by the attack included Oreo cookie manufacturer Mondelez, shipping group Maersk, Russia's Rosneft and the advertising agency WPP.
In a statement, Reckitt Benckiser said: "The attack did disrupt the company's ability to manufacture and distribute products to customers in multiple markets across the RB Group.
"Consequently, we were unable to ship and invoice some orders to customers prior to the close of the quarter.
"Some of our factories are currently still not operating normally but plans are in place to return to full operation."
Reckitt Benckiser said that it expected some of the lost sales to be made up during the third quarter,
"However, the continued production difficulties in some factories mean that we also expect to lose some further revenue permanently."
Reckitt said it now expected like-for-like net revenue growth of 2% for the full year, down from its previous estimate of 3%.
Shares in the company were down more than 2% in morning trading on Thursday.