German chemicals giant Bayer reported on Thursday a heavy fall in first-quarter profits, pulled down by falling sales of crucial weedkillers and drugs. 

The poor results come as the maker of Aspirin faces a delicate transition to a new CEO, and as it contends with calls for a break-up from activist investors. 

Net profit from January to March was €2.2 billion, a 33.8 per cent fall from the same period last year.

Bayer said the slow start to the year was expected and confirmed its outlook for 2023, but expected targets to come in at the lower end of guidance. Its shares fell seven per cent in Frankfurt.

Sales of weedkillers based on the chemical glyphosate dropped sharply due to lower volumes and prices, while prescription drug sales also fell, but less heavily.

Bayer said there were "potential risks" for the rest of 2023 due to "significantly reduced market price expectations for glyphosate-based products". 

Sales of weedkillers based on the chemical glyphosate dropped sharply due to lower volumes and prices, while prescription drug sales also fell, but less heavily

Outgoing CEO Werner Baumann said expected "performance to improve in our other businesses in the second half of the year". Photo: Ina Fassbender / AFP

But CEO Werner Baumann said he continued "to expect performance to improve in our other businesses in the second half of the year".

Group sales fell slightly in the first quarter to €14.4 billion. 

Bayer had benefited in 2022 from rising prices of herbicides due to shortages of key ingredients, but that trend is reversing.

Baumann will be replaced from June by former Roche executive Bill Anderson, following calls from activist investors for a change in direction at the German conglomerate.

The new investors, including Bluebird Capital Partners, want to go further still by splitting the company into an agricultural and a pharmaceutical group.

During his tenure, Baumann oversaw the troubled 2018 takeover of US firm Monsanto for $63 billion.

Bayer inherited Monsanto's legal woes around its Roundup glyphosate-based weedkiller, and has since faced a wave of lawsuits in the United States over claims it causes cancer. 

Bayer denies this.