The arrows indicate the way in which two concepts are associated. Causaly reads and understands text similarly to how humans do and represents the directionality of relationships between 2 Concepts with an arrow. There are four different types of arrows:
A. Upregulate arrow 
This arrow is used in two cases:
i. More of Concept A results in more of Concept B, e.g. A drug induces a side effect.
ii. Less of Concept A results in less of Concept B, e.g. inhibition of a target reduces the progression of the disease.
B. Downregulate arrow 
This arrow is used in two cases:
i. More of Concept A results in less of Concept B, e.g. a drug is a treatment for a disease.
ii. Less of Concept A results in more of B, e.g. inhibition of a target induces progression of the disease.
C. Unidirectional arrow
This arrow is used when Concept A has an effect on Concept B but is neither upregulating nor downregulating e.g a receptor plays a role in disease development.
D. Bidirectional arrow 
This arrow is used when there is an association between A and B, but it is not clear whether there is a causal link or just a correlation/observation, e.g an interaction between 2 targets.
E. Negating arrows 
Refuting statements are also captured in Causaly and are depicted with a strikethrough arrow e.g SARS-CoV antibodies did not prevent pulmonary inflammation.
