X0306 4 2020-02-27 0 0001633070 Axcella Health Inc. AXLA 0001445826 Epstein David R C/O AXCELLA HEALTH INC. 840 MEMORIAL DRIVE CAMBRIDGE MA 02139 1 0 0 0 Common Stock 2020-02-27 4 P 0 12800 3.65 A 66098 D Common Stock 2020-02-28 4 P 0 2005 3.75 A 68103 D The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.56 to $3.74, inclusive. The reporting person undertakes to provide to Axcella Health Inc., any security holder of Axcella Health Inc., or the staff at the Securities and Exchange Commission, upon request, full information regarding the number of shares bought at each separate price within the range set forth in this footnote. The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $3.66 to $3.77, inclusive. The reporting person undertakes to provide to Axcella Health Inc., any security holder of Axcella Health Inc., or the staff at the Securities and Exchange Commission, upon request, full information regarding the number of shares bought at each separate price within the range set forth in this footnote. By: /s/ Heidy King-Jones, as Attorney-in-Fact 2020-03-02